Smoking my first turkey some help please

Not sure about kl8ton's temps cause something seems askew.

I would cook it at 375 dome temp sitting on the grid with a platesetter and drip pan below. You can fit up to a 20lb bird in your large and it will cook in around 3 to 3.5 hours at that temp. Turkey is low fat so there is no advantage going low and slow unless you like dry bird. Ice the breasts for 1 hour prior to cooking and your target temps are 160 for breast and 180 for thighs. Without icing your breast it will reach 180 along with the thigh and be getting dry. Very little wood chips if any at all and fruitwood if you must. Turkey can take on a too heavy smoked taste very easy.
Salt, pepper, and rub the skin with butter before it goes in. I cook 13lb birds in my medium in around 2 hours at 375 dome temp.

You really need to check out the Mad Max Turkey recipe. You can't go wrong. We made it first time last Thanksgiving and it was marvelous. Had it again for Christmas. Can't wait for Thanksgiving again.

http://www.nakedwhiz.com/madmaxturkey.htm

Never use one on turkey or chicken. A big turkey might be learing out the top if its in a vertical stand and freak everyone out. I cook mine right on the BGE grate. If your cramped for room, remove your fire ring to gain another 3" or so.